a) 2 + (81 - x) = -34

81 - x = -34 - 2

81 - x = -36

x = 81 - (-36)

x = 81 + 36

x = 117

b) (-12).x = 60

x = 60 : (-12)

x = -5

c) 12 : (x - 1)² = 3

(x - 1)² = 12 : 3

(x - 1)² = 4

(x - 1)² = 2² (cùng số mũ)

⇒ x - 1 = 2

x = 2 + 1

x = 3

2+(81-x)=-34

      81-x=(-34)-2

      81-x=-36

            x=81-(-36)

            x= 117

(-12)x=60

         x=60:(-12)

          x=-5

Bài 2: 

x=13 nên x+1=14

\(f\left(x\right)=x^{14}-x^{13}\left(x+1\right)+x^{12}\left(x+1\right)-...+x^2\left(x+1\right)-x\left(x+1\right)+14\)

\(=x^{14}-x^{14}-x^{13}+x^{13}-...+x^3+x^2-x^2-x+14\)

=14-x=1

x=13 nên x+1=14

f(x)=x14−x13(x+1)+x12(x+1)−...+x2(x+1)−x(x+1)+14f(x)=x14−x13(x+1)+x12(x+1)−...+x2(x+1)−x(x+1)+14

=x14−x14−x13+x13−...+x3+x2−x2−x+14=x14−x14−x13+x13−...+x3+x2−x2−x+14

=14-x=1

a: =2-81-24-81=-22-162=-184

a) Bạn Nguyễn Lê Phước Thịnh giải rồi nha bạn :)

b) (-9-x+2)+9

=-9-x+2+9

=-9+(-x)+2+9

=(-x)+(-9+2+9)

=(-x)+2

c) 66-(12-x)+(12-66)

=66-12+x+12-66

=x

d) 15-(15-x+93)+93

=15-15+x-93+93

=x

\(3^x-15=12\\ \Rightarrow3^x=27\\ \Rightarrow x=3\)

\(5^{x-1}-12=13\\ \Rightarrow5^{x-1}=25\\ \Rightarrow x=3\)

\(3^{x-2}.9=81\\ \Rightarrow3^{x-2}=9\\ \Rightarrow x=4\)

\(3^{x+1}:9=3\\ \Rightarrow3^{x+1}=27\\ \Rightarrow x=2\)

\(2.x^3=16\\ \Rightarrow x^3=8\\ \Rightarrow x=2\)

\(75:x^2=3\\ \Rightarrow x^2=25\\ \Rightarrow x=\pm2\)

Câu cuối cộng trừ 5

a) (4x - 1)² = 25.9

=> (4x - 1)² = 5² . 3² = 15²

=> 4x - 1 = 15

=> 4x = 16

=> x = 4

b) 2^x + 2^x+3 = 144

=> 2^x + 2^x . 2³ = 144

=> 2^x (1 + 2³) = 144

=> 2^x . 9 = 144

=> 2^x = 16

=> x = 4

c) đề chắc chắn đúng chứ :v

d) (2x + 1)³ - 12 = 15

=> (2x + 1)³ = 27

=> (2x + 1)³ = 3³

=> 2x + 1 = 3 => 2x = 2 => x = 1

2. 2^x = 16 => 2^x = 2⁴ => x = 4

3^x = 81 => 3^x = 3⁴ => x = 4

x³ = 64 => x³ = 4³ => x = 4

x² =81 => x² = 9² => x = 9

Câu c sai đề đó ạ

c) 2.3^x = 10.3¹² + 8.27⁴

tớ 0 biết làm

=> \(\frac{x+2}{10^{10}}+\frac{x+2}{11^{11}}-\frac{x+2}{12^{12}}-\frac{x+2}{13^{13}}=0\)

=> (x + 2)(\(\frac{1}{10^{10}}+\frac{1}{11^{11}}-\frac{1}{12^{12}}-\frac{1}{13^{13}}\)) = 0

=> x + 2 = 0 (vì \(\frac{1}{10^{10}}+\frac{1}{11^{11}}-\frac{1}{12^{12}}-\frac{1}{13^{13}}\)= 0)

=> x = -2